The subject matter disclosed herein generally relates to preventing an emergency over-speed condition in a rotating machine. More specifically, the subject matter relates to a system and method for preventing an emergency over-speed condition in a rotating machine based on a trip overshoot model of the rotating machine.
Rotating machines, for example, gas turbines, steam turbines, wind turbines, and the like, often encounter an emergency over-speed condition due to a loss of counter-load and a delayed cut-off in the energy supply to the rotating component. In such emergency over-speed conditions, the rotating component, such as the turbine rotor, accelerates and reaches rotational speeds beyond its specifications or physical limits. The rotational speed beyond the typical operating parameters can lead to inefficiency, increased maintenance, system failure and possible damage to the equipment or personnel.
Existing methods of preventing such emergency over-speed conditions include setting a speed limit and tripping the rotating machine, if the rotating component exceeds the defined speed limit. Such methods have numerous problems, for example, if the speed limit is set too high, even if the gas turbine (i.e., rotating machine) is tripped, the rotors (i.e., rotating component) may overshoot and reach the emergency over-speed condition due to fuel remaining in the supply lines of the gas turbine. In another example, if the speed limit is set too low, the gas turbine may be tripped even if the rotors might not have reached the emergency over-speed condition. Such false tripping is disadvantageous as it leads to energy losses in the gas turbine, increased down-time, and costly maintenance.
Thus, there is a need for an enhanced system and method for preventing an emergency over-speed condition in rotating machines.